Everyone confuses these two.

Understand it one step at a time

The short runs these in order in about 32 seconds. Here they are written out — pick any step to jump the short straight to it.

1. 1

   Both say event. Not the same

   Same word, two completely different jobs — and picking wrong shows up months later, not on day one.

   Event Grid · vs · Event Hubs

2. 2

   A doorbell and a tape

   A doorbell rings each person once and its job is over. A tape keeps what was recorded and can be rewound.

   push and forget · or store and read

3. 3

   One thing, or a stream?

   “Order placed” matters on its own. “Driver moved” only means something as part of a series.

   Q1 · discrete event or event series

4. 4

   Push, or pull?

   Grid calls your handler and expects a 200. Hubs sits there while you read at whatever pace you manage.

   Q2 · it calls you · you call it

5. 5

   Does anyone read it twice?

   A Grid event is delivered and gone. A Hubs event stays in the retention window for anyone who asks.

   Q3 · no retention · 1-7 days replay

6. 6

   Who retries — them or you?

   Grid retries a failed delivery with backoff and can dead-letter it. Hubs never retries anything.

   Q4 · backoff + DLQ · or your checkpoint

7. 7

   How many per second?

   Discrete business events arrive in the hundreds. Telemetry arrives in the millions, in batches.

   Q5 · reactions · or a firehose

8. 8

   Usually you need both

   Capture writes a file, that write raises a BlobCreated event, and a Function reacts to it. One pipeline.

   Hubs → Capture → Grid → Function

9. 9

   The whole difference in one frame

   Five rows. Save this one — it is the answer interviewers are listening for.

   carries · delivery · afterwards · failure · shape

10. 10

    Doorbell, or tape?

    Ask that one question and you will never mix these two up again — in a design or in an interview.

    Event Grid · Event Hubs